1. Field of the Invention
The present invention relates to a method for manufacturing a multiturn thin film coil preferably for use as a thin film magnetic head such as a tape drive or the like.
2. Description of the Prior Art
There are three known types of construction of a multiturn thin film coil usable as a component of a thin film magnetic head, namely a spiral coil 51 as shown in FIG. 1A, a zigzag coil 52 as shown in FIG. 1B and a helical coil 53 as shown in FIG. 1C, and these are already disclosed in published literature (IEEE Transactions on Magnetics, Vol. MAG-9 No. 3, page 317). FIG. 1A shows a thin film nagnetic head which includes a magnetic core comprising upper and lower magnetic parts 32 and 30 with a magnetic gap 31 therebetween and a spiral coil 51 arranged on a substrate 10. As shown in the figure, the coil 51 on the substrate 10 has its coil pattern planar and expanded in X and Y directions, thus occupying a large area, and hence it is difficult to arrange a plurality of magnetic heads on one substrate 10 at a high density and in parallel in the X direction, thus resulting in difficulty in manufacturing a high density multichannel head. Also, the magnetic core is required to be dimensioned larger in the Y direction with a resultant increase of the magnetic path length, this, in turn, resulting in an increased loss of signal fluxes and interfering with the effect of the multiturn coil.
The zigzag coil 52 of FIG. 1B with its smaller dimension in the X direction permits manufacture of a high-density multichannel head, but also has a defect of increased loss of the signal fluxes due to the increase of the magnetic path length of the magnetic core similar to the case of the aforementioned spiral coil.
As a method for eliminating the aforementioned defects, it has been proposed to use a helical coil 53 shown in FIG. 1C. A conventional method for manufacturing such a helical coil comprises the steps of forming a coil conducting film 55, forming an insulating layer 56, forming a through hole 57 in a coil conducting film 55 and insulating layer 56 and forming a conducting layer for connecting the adjacent coil conducting layer 55 to the through hole 57 layer after layer and to finally complete the multiturn film coil after repetition of these steps. Hence, this type of multiturn film coil is complicated to manufacture.
It is therefore an object of the present invention to provide a method for manufacturing a thin film multiturn coil which has the possibility of decreasing the dimensions of the space occupied thereby on the substrate as well as reducing the magnetic path length of a magnetic core and which is also simple and easy to manufacture.